I purchased ScrapSimple Tools - Styles: Drop Shadows 11701 Super Biggie and they are with all my other styles in PSE. I'm not sure what you mean by 'grouping'. I copy and paste the styles in the following file:

I rename mine so that a 'category' shows first & also start it with a number if I want them to come up at the top of the list--like "1_Shadows_SBA_BasicShadows6501". I still use PSE6, so I have to create an XML file with the same name to get them to show up by their 'new name'.